Electrical switches

Abstract

Electrical switches are described. In one aspect, an electrical switch includes a closed-loop fluid channel, multiple electrodes, and a pressure control system. The closed-loop fluid channel contains an electrically-conductive fluid and an electrically-insulating fluid. Each of the electrodes is in contact with fluid within the fluid channel at a respective location. The pressure control system is operable to change relative fluid pressure within the fluid channel at locations between adjacent electrodes to control splitting of a contiguous region of electrically-conductive fluid electrically connecting a pair of adjacent electrodes and merging of split regions of electrically-conductive fluid.

What is claimed is:  
     
         1 . An electrical switch, comprising: 
 a closed-loop fluid channel containing an electrically-conductive fluid and an electrically-insulating fluid;    multiple electrodes each in contact with fluid within the fluid channel at a respective location; and    a pressure control system operable to change relative fluid pressure within the fluid channel at locations between adjacent electrodes to control splitting of a contiguous region of electrically-conductive fluid electrically connecting a pair of adjacent electrodes and merging of split regions of electrically-conductive fluid.    
     
     
         2 . The electrical switch of  claim 1 , wherein the pressure control system is operable to change relative fluid pressure within the fluid channel to control merging of split regions of electrically-conductive fluid to electrically connect a different pair of adjacent electrodes.  
     
     
         3 . The electrical switch of  claim 1 , wherein the pressure control system is operable to simultaneously change fluid pressure within the fluid channel at locations between electrodes of each of two pairs of adjacent electrodes not sharing a common electrode.  
     
     
         4 . The electrical switch of  claim 1 , wherein the pressure control system is operable to simultaneously change fluid pressure within the fluid channel at locations between electrodes of each of two pairs of adjacent electrodes sharing a common electrode.  
     
     
         5 . The electrical switch of  claim 1 , wherein the fluid channel comprises at least two fluid ports each located between a respective pair of adjacent electrodes, and the pressure control system is coupled to control the flow of non-conducting fluid through the fluid ports.  
     
     
         6 . The electrical switch of  claim 5 , wherein the pressure control system comprises a reservoir of electrically-insulating fluid coupled to a pair of fluid ports.  
     
     
         7 . The electrical switch of  claim 6 , wherein the reservoir is coupled to a pair of fluid ports respectively located between electrodes of two pairs of adjacent electrodes not sharing a common electrode.  
     
     
         8 . The electrical switch of  claim 6 , wherein the reservoir is coupled to a pair of fluid ports respectively located between electrodes of two pairs of adjacent electrodes sharing a common electrode.  
     
     
         9 . The electrical switch of  claim 6 , wherein the reservoir is circumscribed by the fluid channel.  
     
     
         10 . The electrical switch of  claim 6 , wherein the reservoir is located outside the fluid channel.  
     
     
         11 . The electrical switch of  claim 6 , wherein the pressure control system comprises a heater operable to heat electrically-insulating fluid in the reservoir.  
     
     
         12 . The electrical switch of  claim 6 , wherein the pressure control system comprises a second reservoir of electrically-insulating fluid coupled to a second pair of fluid ports.  
     
     
         13 . The electrical switch of  claim 5 , wherein the fluid ports are configured to contain the electrically-conductive fluid in the fluid channel.  
     
     
         14 . The electrical switch of  claim 1 , wherein each of a pair of non-adjacent electrodes is spaced from a third electrode by a distance corresponding to (4×f 1 ) −1 , where f 1  is a first target signal frequency.  
     
     
         15 . The electrical switch of  claim 14 , wherein the non-adjacent electrodes are coupled together by a resistor having an impedance of {square root}{square root over (2)}×Z 0 , where Z 0  is a characteristic impedance produced between the pair of non-adjacent electrodes when electrically-connected together by electrically-conductive fluid within the fluid channel.  
     
     
         16 . The electrical switch of  claim 14 , wherein each of a pair of non-adjacent electrodes is spaced from a fourth electrode by a distance corresponding to (4×f 2 ) −1 , where f 2  is a second target signal frequency.  
     
     
         17 . The electrical switch of  claim 1 , wherein the electrically-conductive fluid has a volume selected to prevent formation of parasitic transmission line elements at electrodes in an open state.  
     
     
         18 . The electrical switch of  claim 1 , wherein the pressure control system is operable to split two volumes of electrically-conductive fluid electrically-connecting two pairs of electrodes and to merge the split electrically-conductive fluid volumes in other regions of the fluid channel to electrically connect two different pairs of electrodes.  
     
     
         19 . The electrical switch of  claim 1 , wherein each of the electrodes has sufficient wettability with respect to the electrically conductive fluid to maintain electrically-conductive fluid over each of the electrodes during transitions from an open state to a closed state and vice versa.  
     
     
         20 . An electrical switch, comprising: 
 a closed-loop fluid channel containing an electrically-conductive fluid and an electrically-insulating fluid and having four fluid ports;    four electrodes each in contact with fluid within the fluid channel at a respective location between a respective pair of adjacent fluid ports; and    two reservoirs of electrically-insulating fluid respectively coupled between a respective pair of non-adjacent fluid ports.    
     
     
         21 . An electrical switch, comprising: 
 a closed-loop fluid channel containing an electrically-conductive fluid and an electrically-insulating fluid and having four fluid ports;    four electrodes each in contact with fluid within the fluid channel at a respective location between a respective pair of adjacent fluid ports; and    two reservoirs of electrically-insulating fluid respectively coupled between a respective pair of adjacent fluid ports.